Abstract: A reproduction apparatus for an optical recording medium that has a convex pit recording layer, in which pits are formed in a convex shape viewed from a laser incidence side, and a concave pit recording layer, in which pits are formed in a concave shape viewed from the laser incidence side, as recording layers in which data is recorded by pit strings, the pits being formed with a depth that is set in a range of ?/4.5 to ?/6 with respect to a laser wavelength ?, including: an optical head section that irradiates laser beams on the recording layers and detects reflected light information to read out information recorded in the recording layers; a tracking error signal generating section that generates a tracking signal; a polarity switching section that switches a polarity of the tracking error signal; and a tracking servo section that performs a tracking servo operation.

Abstract: A magnetic card of the invention comprises a card substrate 11 on which a magnetic layer 12, a thin-film layer 13 formed of a metal or a metal compound for concealing the magnetic layer, a printed layer 14 and a volume hologram layer 15 are successively provided, wherein magnetic information is recorded on or read from a volume hologram layer side. The volume hologram layer 15 is composed essentially of a photosensitive material comprising a cationic polymerizable compound, a radical polymerizable compound, a photo-radical polymerization initiator system that is sensitive to light of a specific wavelength to polymerize the radical polymerizable compound, and a photo-cationic polymerization initiator system that is less sensitive to the light of a specific wavelength but sensitive to light of another wavelength to polymerize the cationic polymerizable compound.

Abstract: A reproduction apparatus for an optical recording medium that has a convex pit recording layer, in which pits are formed in a convex shape viewed from a laser incidence side, and a concave pit recording layer, in which pits are formed in a concave shape viewed from the laser incidence side, as recording layers in which data is recorded by pit strings, the pits being formed with a depth that is set in a range of ?/4.5 to ?/6 with respect to a laser wavelength ?, including: an optical head section that irradiates laser beams on the recording layers and detects reflected light information to read out information recorded in the recording layers; a tracking error signal generating section that generates a tracking signal; a polarity switching section that switches a polarity of the tracking error signal; and a tracking servo section that performs a tracking servo operation.

Abstract: A magnetic card of the invention comprises a card substrate 11 on which a magnetic layer 12, a thin-film layer 13 formed of a metal or a metal compound for concealing the magnetic layer, a printed layer 14 and a volume hologram layer 15 are successively provided, wherein magnetic information is recorded on or read from a volume hologram layer side. The volume hologram layer 15 is composed essentially of a photosensitive material comprising a cationic polymerizable compound, a radical polymerizable compound, a photo-radical polymerization initiator system that is sensitive to light of a specific wavelength to polymerize the radical polymerizable compound, and a photo-cationic polymerization initiator system that is less sensitive to the light of a specific wavelength but sensitive to light of another wavelength to polymerize the cationic polymerizable compound.